Illuminated and isolated electrosurgical apparatus

ABSTRACT

Unintended current flow or plasma discharge has been observed in known illuminated electrosurgical devices having a metallic tubular heat sink surrounding a conductive electrode and an illumination element, and having a distal outer edge that abuts against the light emitting element. An insulating, shielding or other isolating element that prevents or discourages unintended plasma formation between the distal outer edge and nearby patient tissue can reduce the potential for tissue damage to a patient or injury to a surgeon.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No.16/232,705, filed Dec. 26, 2018 (now U.S. Pat. No. 10,806,504 B2), whichis a continuation of U.S. application Ser. No. 15/887,503, filed Feb. 2,2018 (now U.S. Pat. No. 10,194,975 B1), which claims priority to U.S.Provisional Application No. 62/531,188 filed Jul. 11, 2017, the entiredisclosures of which are incorporated herein by reference.

TECHNICAL FIELD

The present application relates to illuminated electrosurgical devices.

BACKGROUND

Illuminated electrosurgical devices generally include a hand piece(handle) ergonomically adapted for ease of manipulation by a surgeonduring surgery, and for positioning an energy tip of the device todeliver electrical energy to a target tissue for tissue cutting orcoagulation. An electrode and electrical supply cable are generallydisposed within the handle, traversing from the handle's proximal endthrough the handle body, and terminating in an energy discharge tip atthe distal end of the device. The electrical supply cable typically isconnected to an energy source, such as a radiofrequency (RF) energygenerator.

The handle or other portion of the device may include an illuminationelement for illuminating the surgical field. Light may be conductedtowards the energy discharge tip and directed onto the surgical fieldvia an optical waveguide coupled to the handle or disposed within thehandle. The electrode may be disposed within the optical waveguide, ordisposed alongside the waveguide. The electrode and waveguide may bedisposed within a suitable supporting structure (for example, acylindrical metal tube), that may be slidably extendable or retractableto permit the electrosurgical device to elongate or shorten as needed totreat the surgical site.

SUMMARY

The present invention provides an improved illuminated electrosurgicaldevice having reduced tendency to cause unintended current flow orplasma discharge and patient injury. In one embodiment, the devicecomprises:

-   -   a) a handle;    -   b) a conductive electrode supported by the handle and having a        tip for cutting or cauterizing tissue;    -   c) an illumination element coupled to the handle, the        illumination element comprising a light source, an optical        waveguide, and a light emitting element illuminating the        electrode tip;    -   d) a metallic tubular heat sink surrounding at least part of the        conductive electrode and illumination element and having a        distal outer edge that abuts against the light emitting element;        and    -   e) an insulating, shielding or other isolating element that        prevents or discourages unintended current flow or plasma        formation between the distal outer edge and nearby patient        tissue.

The disclosed invention addresses shortcomings in currentelectrosurgical devices, by preventing or discouraging unintended RFenergy release and accidental injury to the patient or surgeon. Theinvention includes modification of a known device to insulate, isolateor shield the distal end of a metal heat sink on such device (forexample, by adding electrical insulation over the distal end), therebypreventing or discouraging the unwanted release of energy.

The above summary is not intended to describe each illustratedembodiment or every implementation of the disclosed subject matter. Thedetails of one or more embodiments of the invention are set forth in theaccompanying Drawing and this Specification. Other features, objects,and advantages of the invention will be apparent from the Drawing, theSpecification and the claims.

BRIEF DESCRIPTION OF THE DRAWING

The disclosed subject matter may be more completely understood from theaccompanying figures, in which:

FIG. 1 is a perspective view, partially in section, of a knownilluminated electrosurgical device;

FIG. 2 is an exploded view of distal components of the FIG. 1 device;

FIG. 3 is a cross-sectional view of the assembled FIG. 2 components;

FIG. 4 through FIG. 10 are sectional views of various embodiments of theinvention; and

FIG. 11 is a photograph showing the unintended discharge of energy fromthe FIG. 1 device onto nearby tissue.

Like reference symbols in the various figures of the Drawing indicatelike elements. The elements in the Drawing are not to scale.

DEFINITIONS

Unless the context indicates otherwise, the following terms shall havethe following meaning and shall be applicable both to the singular andplural:

The terms “conductor”, “conductive” and “conducting” mean electricallyconductive, and refer to materials that readily permit the flow ofelectrical current through such material. Conductive materials may insome instances be thermally conductive but are not always so. Materialssuch as carbon black, moisture and metals are representative conductingmaterials.

The term “electrosurgical device” means an electrical device designedfor handheld use by a surgeon to dispense RF or other energy through thetip of an electrode into target surgical tissue, in order to cut orcoagulate the tissue during a surgical procedure.

The terms “insulator”, “insulation” and “insulating” mean electricallyinsulating, and refer to dielectric materials that permit little, ifany, flow of electrical current through such material. Insulatingmaterials may in some instances be thermal insulators but are not alwaysso. Materials such as glass, metal oxides, porcelain, paper, plastics,polymers and rubbers are representative insulating materials.

The terms “radiofrequency energy” or “RF” energy mean energy from theelectromagnetic spectrum having a frequency between about 3 kilohertz (3kHz) and about 300 gigahertz (300 GHz).

DETAILED DESCRIPTION

Surgical devices should not unduly impede the surgeon's view of theoperating field. This is particularly troublesome in electrosurgicaldevices, especially those with extra features beyond energy delivery,such as added illumination, smoke evacuation, saline delivery, or otherancillary features.

In the case of an electrosurgical device which also provides addedillumination (viz. light directed at the surgical field), the lightdesirably is emitted near the distal end of the device, where any addedbulk may also directly impede the surgeon's view. Device designers haveconsequently sought to minimize the distal profile of such devices, andto make the associated components as small, thin and few in number aspossible.

FIG. 1 shows a known electrosurgical device 100 supplied by Invuity,Inc. as the PhotonBlade™ electrosurgical device. Device 100 includes ahandle 102 in which is mounted a tubular metal heat sink 104 that can beslidably extended from or pushed into handle 102 and fixed in place witha collet or other locking mechanism (not shown in FIG. 1 ). Doing sopermits a surgeon to vary the length of device 100 as may be needed forparticular surgical procedures. Conductive electrode 106 is partiallyhoused within heat sink 104, and includes a distally projecting RFenergy discharge tip 108 intended to emit RF energy to cut or cauterizehuman or animal tissue. Electrode 106 also includes a conductive legportion 110 extending towards handle 102, and intended to be connected(e.g., via an electrical connector, solder or other suitable connectionnot shown in FIG. 1 ) with a conductive cable (also not shown in FIG. 1) that passes through handle 102 and supplies RF energy to electrode106. Optionally, the electrode 106 may include an enamel insulativecoating such as those disclosed in U.S. Pat. No. 7,736,361 B2. Legportion 110 resides in a slot 112 formed in optical waveguide 116 andpasses through a notch 118 in light source 120, shown here as a circuitboard housing a light emitting diode (LED) 122. Light from LED 122 iscaptured by parabolic light collector 124 and transmitted throughwaveguide 116 towards translucent light emitting element 126. A layer ofcladding 128 surrounds optical waveguide 116 and is said to providedesired optical properties to optical waveguide 116. The front or distalend of heat sink 104 abuts against the rear or proximal face of lightemitting element 126. During use of device 100, light is emitted fromlenslets 130 on the front face of element 126, as well as from outeredge 132 of element 126.

FIG. 2 shows an exploded view of distal components of the FIG. 1 device.Optical waveguide 116, collector 124 and light emitting element 126 arerespectively formed from half guides 116 a and 116 b, half collectors124 a and 124 b, and half elements 126 a and 126 b. Slot 114 andcladding 122 have the shapes shown in FIG. 2 . As supplied in device100, tubular metal heat sink 104 has a thin outer layer of insulation(not labeled in FIG. 2 ). Cut end 134 of heat sink 104 is however notinsulated, and cut end 134, and especially its outer edge 136, have ahigh electrical potential and can promote unintended RF discharge.

FIG. 3 is a cross-sectional view of the assembled FIG. 2 components. Cutend 134 abuts against the rear face of light emitting element 126. ArrowP indicates a point from which unintended RF energy may be emitted fromdevice 100 toward tissue beneath device 100, especially when high powerlevels (e.g., power levels of at least 10 watts, at least 20 watts, atleast 30 watts, at least 40 watts or at least 50 watts) are employed.When such emission occurs, current can flow or plasma can form betweencut end 134 or outer edge 136 and nearby tissue, causing tissue burningat other than the intended surgical site, while meanwhile depoweringelectrode 106 and preventing tip 108 from cutting or cauterizing targettissue.

FIG. 11 is a photograph showing such unintended current flow or plasmaformation, in a simulated electrosurgery performed as described inExample 1. Burn marks A and B were caused by two prior unintended plasmabursts, and an unintended plasma formed under the distal end of heatsink 104.

FIG. 4 shows one solution to the unintended current flow or plasmageneration problem discussed above. Light emitting element 426 has alarger outside diameter than heat sink 104, and includes a rim portion428 that extends proximally along at least a portion of heat sink 104(e.g., at least 1 mm, at least 2 mm, at least 3 mm, at least 4 mm or atleast 5 mm, and up to 10 mm, up to 9 mm or up to 8 mm) and hassufficient thickness (e.g., at least 0.2 mm, at least 0.3 mm, at least0.4 mm or at least 0.5 mm, and up to 2 mm, up to 1.8 mm, up to 1.6 mm orup to 1.5 mm) so that cut end 134 and edge 136 are buried within andinsulated by rim portion 428. This improves the electrical isolation ofcut end 134, and discourages or prevents unintended current flow orplasma generation. The thickness and length of rim portion 428 (and thethickness, shape or composition of the other insulating, shielding orother isolating measures discussed below) may be empirically determined,for example by repeating the chicken tissue test discussed above and inExample 1, or by measuring breakdown voltage using the Hi-Pot testdiscussed in Example 2. In certain embodiments, the added insulating,shielding or other isolating measure is sufficient to prevent unintendedcurrent flow or plasma generation when using the Example 1 experimentalsetup and an operating power of 10 watts, 20 watts, 30 watts, 40 wattsor 50 watts, while contacting the chicken tissue with the light emittingelement, or while laying the heat sink atop the tissue. In certain otherembodiments, the added insulating, shielding or other isolating measureis sufficient to increase the breakdown voltage using the Example 2Hi-Pot test and the metal heat sink alone without the handle and tip, toat least 2 KV RMS @20 seconds, at least 3 KV RMS @20 seconds or at least4 KV RMS @20 seconds.

FIG. 5 shows another solution to the unintended current flow or plasmageneration problem discussed above. A bead 502 of a suitable curable orhardenable insulating material (e.g., a room temperature vulcanizingsilicone resin, a curable thermoset epoxy or other preferablythermosetting insulating material, a hardenable inorganic liquid such aswaterglass or a hardenable inorganic paste such as plaster of Paris) isplaced over outer edge 132 of light emitting element 126 and over outeredge 136 and at least a portion of the distal end of heat sink 104, andthen cured or hardened. In an embodiment, a bead of the insulatingmaterial is applied to light emitting element 126 before heat sink 104is abutted against element 126, followed by pushing heat sink 104 andelement 126 together, so that cut end 134 will contact and be embeddedin bead 502. If a translucent or transparent insulating material isemployed for bead 502, or if the width of bead 502 is such that aportion of outer edge 132 of element 126 remains uncovered, then lightmay continue to be emitted from outer edge 132 during surgery. This maybe desirable in some instances, but may be undesirable in others. Forexample, if an opaque insulating material is employed for bead 502,light may no longer be emitted from outer edge 132, and glare may bereduced or eliminated during surgery. If desired, the axial length ofelement 126 may be increased so that outer edge 132 may be made wider,thereby permitting bead 502 to be made wider as well while preserving orlargely preserving the original width of outer edge 132. In any event,the thickness, width and composition of bead 502 may be empiricallydetermined using the Example 1 or Example 2 procedures discussed abovein connection with the FIG. 4 embodiment. Bead 502 may for example havea thickness of at least 0.1 mm, at least 0.2 mm, at least 0.3 mm, atleast 0.4 mm or at least 0.5 mm, and up to 2 mm, up to 1.5 mm or up to 1mm. Bead 502 may for example have a width of at least 1 mm, at least 2mm, at least 3 mm, at least 4 mm or at least 5 mm, and up to 10 mm, upto 9 mm or up to 8 mm.

FIG. 6 shows another solution to the unintended current flow or plasmageneration problem discussed above. An insulating coating 602(preferably a coating that is thicker, less conductive, or both thickerand less conductive than the insulative layer currently employed on heatsink 104) is coated onto cut end 134 and over at least a portion of heatsink 104. Coating 602 may for example be a paint, a vapor-depositedpolymeric film, a cured or hardened layer of an organic or inorganicmaterial, or a layer of glass. In a preferred embodiment, coating 602also covers at least a portion of the inner sidewall of heat sink 104,and may for example extend along heat sink 104 past the proximal end ofleg 110. The thickness, width, composition and configuration of coating602 may be empirically determined using the Example 1 or Example 2procedures discussed above in connection with the FIG. 4 embodiment.Coating 602 may for example have a thickness of at least 0.05 mm, atleast 0.1 mm, at least 0.2 mm, at least 0.3 mm, at least 0.4 mm or atleast 0.5 mm, and up to 2 mm, up to 1.5 mm or up to 1 mm. Coating 602may for example extend proximally away from cut edge 134 along the inneror outer sidewalls of heat sink 104 for a distance of at least 1 mm, atleast 2 mm, at least 3 mm, at least 4 mm or at least 5 mm, and up to theentire length of heat sink 104, past the proximal end of leg 110, or forat least the distal 20 mm, 10 mm or 8 mm of heat sink 104.

FIG. 7 shows another solution to the unintended current flow or plasmageneration problem discussed above. A length of rubber or plastic tubing702 is placed over cut end 134 and over at least a portion of outer edge132 of element 126 and over at least a portion of the distal end of heatsink 104, to form an insulating sleeve or collar. Tubing 702 may forexample be an elastomeric tubing material such as surgical or othertubing made from natural rubber, fluoroelastomer, latex, silicone orpolyvinyl chloride (PVC). Tubing 702 may also be a heat-shrinkabletubing such as a polyolefin, neoprene or fluoropolymer material. Thethickness, width and composition of tubing 702 may be empiricallydetermined using the Example 1 or Example 2 procedures discussed abovein connection with the FIG. 4 embodiment. Tubing 702 may for examplehave a thickness of at least 0.1 mm, at least 0.2 mm, at least 0.3 mm,at least 0.4 mm or at least 0.5 mm, and up to 2 mm, up to 1.5 mm or upto 1 mm. Tubing 702 may for example have a width of at least 2 mm, atleast 3 mm, at least 4 mm or at least 5 mm, and up to 10 mm, up to 9 mmor up to 8 mm.

FIG. 8 shows another solution to the unintended current flow or plasmageneration problem discussed above. A least one and preferably two ormore turns of adhesive tape (e.g., PVC electrical tape) 802 are wrappedaround at least a portion of outer edge 132 of element 126, over cut end134 and over at least a portion of the distal end of heat sink 104. Aspiral wrap pattern or a wrap pattern in which the ends of the tape arealigned with and overlap one another may be used. The thickness, width,composition and number of turns of tape 802 may be empiricallydetermined using the Example 1 or Example 2 procedures discussed abovein connection with the FIG. 4 embodiment. Tape 802 may for example havea thickness of at least 0.1 mm, at least 0.2 mm or at least 0.3 mm, andup to 2 mm, up to 1.5 mm or up to 1 mm. Tape 702 may for example have awidth of at least 2 mm, at least 3 mm, at least 4 mm or at least 5 mm,and up to 20 mm, up to 16 mm or up to 10 mm.

FIG. 9 shows another solution to the unintended current flow or plasmageneration problem discussed above. The thickness, composition or boththickness and composition of cladding 928 are changed to increase thebreakdown voltage exhibited by heat sink 104. The extent to which suchchanges are made may be empirically determined using the Example 1 orExample 2 procedures discussed above in connection with the FIG. 4embodiment. Cladding 928 may for example have a thickness of at least0.1 mm, at least 0.2 mm or at least 0.3 mm, and up to 2 mm, up to 1.5 mmor up to 1 mm, and may be made from a variety of suitable dielectricmaterials including ceramics, glass, paper, plastics and rubber.

FIG. 10 shows another solution to the unintended current flow or plasmageneration problem discussed above. Some or all of the portions ofelectrode 106 that contact light emitting element 126 or that extendthrough heat sink 104 (and especially those parts of electrode 106 suchas leg 110 which are positioned near the inner wall of heat sink 104)can be coated with a layer 1040 of a suitable insulating material toincrease the breakdown voltage exhibited by heat sink 104. Thethickness, arrangement and composition of such a coating may beempirically determined using the Example 1 or Example 2 proceduresdiscussed above in connection with the FIG. 4 embodiment. Coating 1040may for example have a thickness of at least 0.1 mm, at least 0.2 mm orat least 0.3 mm, and up to 2 mm, up to 1.5 mm or up to 1 mm, and may bemade from a variety of suitable dielectric materials including ceramics,glass, paper, plastics and rubber.

In an additional embodiment, shown in FIG. 9 , a continuous ordiscontinuous (e.g., screened) conductive layer 930 may be placedbetween cladding 928 and heat shield 104, and connected to an earthground. Doing so can reduce the voltage potential at cut end 134 andalong the length of heat shield 104, and discourage unintended externalcurrent flow or plasma generation. The additional conductive layer 930may if desired be included as a part of cladding 928 (for example, as anouter layer) or may be included as a part of heat sink 104 (for example,as an inner layer separated from the inner metallic wall of heat sink104 by a suitable insulating layer on such inner wall. When such anadditional conductive layer 930 is employed, it may also be necessary ordesirable to employ additional insulating measures on portions of thedevice inside the additional conductive layer 930 (for example, bymaking changes to cladding 928 as discussed in connection with FIG. 9 ,or by coating portions of electrode 106 as discussed in connection withFIG. 10 ), so as to avoid undesirable internal current leakage orinternal current flow or plasma generation during use.

In an additional embodiment, not shown in the Drawing, electrode 106 andone or more of optical waveguide 116, light source 120, light collector124 and light emitting element 126 can be redesigned so that thoseportions of electrode 106 that lie inside heat sink 104 are further fromthe inner wall of heat 110 than is presently the case in device 100. Inone embodiment, electrode 106 may be made narrower as it passes throughlight emitting element 126 and optical waveguide 116. In the same oranother embodiment, leg 110 is rerouted so that it runs through thecenter of device 100 rather than near the inner wall of heat sink 104,and light source 120 and light collector 124 are modified so that LED122 is not in the way of leg 110 and optical waveguide 116 is edge-litrather than centrally illuminated.

In an additional embodiment, not shown in the Drawing, all or at least adistal portion of heat sink 104 is made from an insulating materialrather than from metal. Exemplary such materials include ceramics, glassand plastics. The thickness, composition and configuration of such aninsulating material may be empirically determined using the Example 1 orExample 2 procedures discussed above in connection with the FIG. 4embodiment.

The various insulation materials mentioned above may be interchanged forone another or replaced or combined with a variety of other insulationmaterials. Preferred insulation materials include acrylics, acrylates,acrylonitrile-butadiene-styrene (ABS) copolymers, cyanoacrylateadhesives, epoxies, fluorinated ethylene propylene (FEP) elastomers,polycarbonates, polyimides, polytetrafluoroethylene (PTFE) plastics,natural and synthetic rubbers, non-conductive adhesives, RTV and othersilicone rubbers, polyurethanes, inorganic dielectrics, glass, ceramics,porcelain, and other insulating materials that will be familiar topersons having ordinary skill in the art.

EXAMPLES Example 1 Simulated Electrosurgery

Simulated electrosurgery was performed using a skinless chicken breast,a Valleylab Force FX™ isolated output electrosurgical generator set to50 watt, high coagulation output, and device 100. The device hadpreviously been used in an electrosurgical procedure. The results areshown in FIG. 11 . Burn marks A and B were caused by two priorunintended current or plasma bursts when device 100 was held at an angleand light emitting element 126 was allowed to contact the tissue. Anunintended plasma was visible under the distal end of heat sink 104.Meanwhile electrode 106 is depowered and energy discharge tip 108 cannotbe used for cutting or cauterizing target tissue. The tendency forunintended plasma generation to occur increased significantly wheneverdevice 100 was held at an acute angle with respect to the chickentissue, and increased as the distance from end 134 to the tissuediminished. At a sufficiently small distance or upon contact of lightemitting element 126 against the tissue, an unintended plasma dischargecommenced. Unintended plasma generation also occurred whenever heat sink104 was laid atop the tissue. The plasma continued until device 100 waspulled or tipped away from the tissue, and meanwhile the tissue becamecharred and the odor of cooked chicken emanated from the burn sites.Upon removal from the tissue, a dark discolored region was visible nearthe portion of edge 134 that had been closest to the tissue, and thecorresponding bluish insulation layer on heat sink 104 appeared to havebeen burned away.

These results suggest that in tight anatomical spaces where contactbetween the edge of the metal heat sink tube and tissue cannot beavoided, tissue damage will likely occur due to RF energy releasebetween the distal edge of the metal tube and the surgical targettissue, particularly when the device is used for coagulation.

Example 2 IEC Hi-Pot Test

International Standard IEC 60601-2-2 (the IEC Hi-Pot Test) may be usedto test dielectric strength and leakage current for both monopolar andbipolar high frequency electrosurgical devices, and their individualcomponents. An Invuity PhotonBlade electrosurgical device that hadpreviously been used in a surgical procedure was disassembled and itscomponents subjected to the IEC Hi-Pot Test to determine breakdownvoltages and evaluate potential energy leakage for various componentsand subassemblies. The Valleylab Force FX™ electrosurgical generatorused in Example 1 was employed for the IEC test. The Force FX generatorhas a maximum voltage output of 3.89 KV RMS. Each of the handle 102 only(without the heat sink 110 and the components it contains); the handle102 with the heat sink 110 and the components it contains (but withoutbuttons); the handle 102 and its cable (but without buttons and withoutheat sink 110 and the components it contains); and the heat sink 110 andsome of components it contains (but without handle 102 and the exposedportion of electrode 106) were evaluated for potential energy leakage.The test results are shown below in Table 1.

TABLE 1 Test Setup Failure Voltage Handle Only (no Heat Sink) 3.89 KVRMS @ 20 seconds Handle and Heat Sink (no Buttons)  2.7 KV RMS @ 20seconds Handle and Cable (no Buttons and no Heat 3.01 KV RMS @ 20seconds Sink) Heat Sink Only (no Handle or Tip)  1.6 KV RMS @ 20 seconds

The results in Table 1 show that each of the tested components may havevoltage breakdown issues, with the heat sink representing the weakesttested link.

Various embodiments of systems, devices, and methods have been describedherein. These embodiments are given only by way of example and are notintended to limit the scope of the claimed invention. It should beappreciated, moreover, that the various features of the embodiments thathave been described may be combined in various ways to produce numerousadditional embodiments. Moreover, while various materials, dimensions,shapes, configurations and locations, etc. have been described for usewith disclosed embodiments, others besides those disclosed may beutilized without exceeding the scope of the claimed inventions. Forexample, persons of ordinary skill in the relevant art will recognizethat the subject matter hereof may comprise fewer features thanillustrated in any individual embodiment described above. Theembodiments described herein are not meant to be an exhaustivepresentation of the ways in which the various features of the subjectmatter hereof may be combined. Accordingly, the embodiments are notmutually exclusive combinations of features; rather, the variousembodiments can comprise a combination of different individual featuresselected from different individual embodiments, as understood by personsof ordinary skill in the art. Moreover, elements described with respectto one embodiment can be implemented in other embodiments even when notdescribed in such embodiments unless otherwise noted.

Although a dependent claim may refer in the claims to a specificcombination with one or more other claims, other embodiments can alsoinclude a combination of the dependent claim with the subject matter ofeach other dependent claim or a combination of one or more features withother dependent or independent claims. Such combinations are proposedherein unless it is stated that a specific combination is not intended.

For purposes of interpreting the claims, it is expressly intended thatthe provisions of 35 U.S.C. § 112(f) are not to be invoked unless thespecific terms “means for” or “step for” are recited in a claim.

The invention claimed is:
 1. An electrosurgical device comprising: a) ahandle; b) a conductive electrode supported by the handle and having atip for cutting or cauterizing tissue; c) an illumination elementcoupled to the handle, the illumination element comprising a lightsource, an optical waveguide, and a light emitting element illuminatingthe electrode tip; d) a metallic tubular heat sink surrounding at leastpart of the conductive electrode and illumination element and having adistal outer edge that abuts against the light emitting element; and e)an insulating, shielding or other isolating element that prevents ordiscourages unintended current flow or plasma formation between thedistal outer edge and nearby patient tissue wherein the heat sink hasinner and outer sidewalls; the insulating, shielding or other isolatingelement covers at least a portion of the inner sidewall; the electrodehas a proximal end; and the insulating, shielding or other isolatingelement extends along the inner sidewall past such proximal end.
 2. Thedevice of claim 1, wherein the insulating, shielding or other isolatingelement also surrounds the distal outer edge.
 3. The device of claim 1,wherein the insulating, shielding or other isolating element also coversat least a portion of the outer sidewall.
 4. The device of claim 1,wherein the insulating, shielding or other isolating element alsocomprises an insulating coating on the distal outer edge and over atleast a portion of the heat sink.
 5. The device of claim 1, wherein theinsulating, shielding or other isolating element comprises a paint,vapor-deposited polymeric film, cured or hardened layer of an organic orinorganic material, or layer of glass.
 6. The device of claim 1, whereinthe insulating, shielding or other isolating element also comprises alength of rubber or plastic tubing placed over the distal outer edge,over at least a portion of the light emitting element, and over at leasta portion of the distal end of the heat sink, to form an insulatingsleeve or collar.
 7. The device of claim 6, wherein the tubing comprisesan elastomeric natural rubber, fluoroelastomer, latex, silicone orpolyvinyl chloride.
 8. The device of claim 6, wherein the tubingcomprises heat-shrinkable tubing.
 9. The device of claim 1, wherein theinsulating, shielding or other isolating element also comprises claddingthat surrounds the optical waveguide and whose thickness, composition orboth thickness and composition reduce the breakdown voltage exhibited bythe heat sink.
 10. The device of claim 1, wherein portions of theelectrode contact the light emitting element and extend through the heatsink and are coated with insulating material layer that reduces thebreakdown voltage exhibited by heat sink.
 11. The device of claim 1,wherein the insulating, shielding or other isolating element comprisesan insulation material selected from acrylics, acrylates,acrylonitrile-butadiene-styrene (ABS) copolymers, cyanoacrylateadhesives, epoxies, fluorinated ethylene propylene (FEP) elastomers,polycarbonates, polyimides, polytetrafluoroethylene (PTFE) plastics,natural and synthetic rubbers, non-conductive adhesives, RTV and othersilicone rubbers, polyurethanes, inorganic dielectrics, glass, ceramicsor porcelain.
 12. The device of claim 1, wherein the insulating,shielding or other isolating element has a thickness of at least about0.2 mm.
 13. The device of claim 1, wherein the insulating, shielding orother isolating element has a thickness of at least about 0.4 mm. 14.The device of claim 1, wherein the device does not release RF energyfrom a site other than the electrode tip.
 15. An electrosurgical devicecomprising: a) a handle; b) a conductive electrode supported by thehandle and having a tip for cutting or cauterizing tissue; c) anillumination element coupled to the handle, the illumination elementcomprising a light source, an optical waveguide, and a light emittingelement illuminating the electrode tip; d) a metallic tubular heat sinksurrounding at least part of the conductive electrode and illuminationelement and having a distal outer edge that abuts against the lightemitting element; and e) an insulating, shielding or other isolatingelement that prevents or discourages unintended current flow or plasmaformation between the distal outer edge and nearby patient tissuewherein the heat sink has inner and outer sidewalls; the insulating,shielding or other isolating element covers at least a portion of theinner sidewall; and the light emitting element has a larger outsidediameter than the heat sink and includes a rim portion that extendsproximally along at least a portion of the heat sink, and the distalouter edge is buried within and insulated by the rim portion.
 16. Anelectrosurgical device comprising: a) a handle; b) a conductiveelectrode supported by the handle and having a tip for cutting orcauterizing tissue; c) an illumination element coupled to the handle,the illumination element comprising a light source, an opticalwaveguide, and a light emitting element illuminating the electrode tip;d) a metallic tubular heat sink surrounding at least part of theconductive electrode and illumination element and having a distal outeredge that abuts against the light emitting element; and e) aninsulating, shielding or other isolating element that prevents ordiscourages unintended current flow or plasma formation between thedistal outer edge and nearby patient tissue wherein the heat sink hasinner and outer sidewalls; the insulating, shielding or other isolatingelement covers at least a portion of the inner sidewall; the insulating,shielding or other isolating element also comprises cladding thatsurrounds the optical waveguide and whose thickness, composition or boththickness and composition reduce the breakdown voltage exhibited by theheat sink; and the device comprises a continuous or discontinuousconductive layer between the cladding and heat shield and connected toan earth ground.
 17. An electrosurgical device comprising: a) a handle;b) a conductive electrode supported by the handle and having a tip forcutting or cauterizing tissue; c) an illumination element coupled to thehandle, the illumination element comprising a light source, an opticalwaveguide, and a light emitting element illuminating the electrode tip;d) a metallic tubular heat sink surrounding at least part of theconductive electrode and illumination element and having a distal outeredge that abuts against the light emitting element; and e) aninsulating, shielding or other isolating element that prevents ordiscourages unintended current flow or plasma formation between thedistal outer edge and nearby patient tissue wherein the heat sink hasinner and outer sidewalls; the insulating, shielding or other isolatingelement covers at least a portion of the inner sidewall; and all or atleast a distal portion of the heat sink is made from an insulatingmaterial rather than from metal.
 18. An electrosurgical devicecomprising: a) a handle; b) a conductive electrode supported by thehandle and having a tip for cutting or cauterizing tissue; c) anillumination element coupled to the handle, the illumination elementcomprising a light source, an optical waveguide, and a light emittingelement illuminating the electrode tip; d) a metallic tubular heat sinksurrounding at least part of the conductive electrode and illuminationelement and having a distal outer edge that abuts against the lightemitting element; and e) an insulating, shielding or other isolatingelement that prevents or discourages unintended current flow or plasmaformation between the distal outer edge and nearby patient tissuewherein the heat sink has inner and outer sidewalls; the insulating,shielding or other isolating element covers at least a portion of theinner sidewall; and the insulating, shielding or other isolating elementprevents unintended current flow or plasma generation when using anoperating power of 10 watts while contacting chicken tissue with thelight emitting element, or while laying the heat sink atop such tissue.19. The device of claim 18, wherein the insulating, shielding or otherisolating element prevents unintended current flow or plasma generationwhen using an operating power of 30 watts while contacting chickentissue with the light emitting element, or while laying the heat sinkatop such tissue.
 20. The device of claim 18, wherein the insulating,shielding or other isolating element prevents unintended current flow orplasma generation when using an operating power of 50 watts whilecontacting chicken tissue with the light emitting element, or whilelaying the heat sink atop such tissue.
 21. The device of claim 18,wherein the insulating, shielding or other isolating element increasesthe breakdown voltage of the heat sink, measured without the handle andtip, to at least 2 KV RMS @ 20 seconds.
 22. The device of claim 18,wherein the insulating, shielding or other isolating element increasesthe breakdown voltage of the heat sink, measured without the handle andtip, to at least 3 KV RMS @ 20 seconds.
 23. The device of claim 18,wherein the insulating, shielding or other isolating element increasesthe breakdown voltage of the heat sink, measured without the handle andtip, to at least 4 KV RMS @ 20 seconds.